title: Persistence of exotic Newcastle disease virus (ENDV) in laboratory infected Musca domestica and Fannia canicularis.
abstract: House flies (Musca domestica) and little house flies (Fannia canicularis) were examined for their ability to take up and harbor a velogenic strain of exotic Newcastle disease virus (ENDV) (family Paramyxoviridae, genus Avulavirus). Laboratory-reared flies were allowed to feed on evaporated milk containing ENDV at a virus concentration of 10(8.3) egg infectious dose (EID)50/0.1 ml or on poultry feces containing an ENDV titer of 10(5.8) EID50/0.1 g. Flies exposed to either infectious food source for 24 hr became transiently infected with virus. Virus persisted predominantly in the mid- and hindgut, with relatively little virus isolated from the remainder of the fly body. Virus persisted similarly in both fly species that were fed evaporated milk containing ENDV, with a maximum ENDV titer of 10(5.98) EID50/fly for the house fly and 10(4.78) EID50/fly for the little house fly at 1 day postexposure; titers decreased on subsequent days to 10(2.38) EID50/fly for house fly and > or = 1 EID50/fly for little house fly at 5 days postexposure. Both fly species acquired viral titers greater than the infective dose for a susceptible chicken (10(3.0) EID50-10(4.0) EID50). In addition, flies fed evaporated milk containing a high titer of ENDV maintained viral titers above the infective dose for up to 4 days postexposure to the infectious food source. Flies fed on infective feces retained a chicken infective dose for only one day. The decrease in viral titer over time was significantly explained by logistic regression for both fly species (P < 0.05). The slope of the regression line was not different for the two fly species (P < 0.05), indicating a similar rate of virus loss.
authors.affiliation: Department of Entomology, University of California, Riverside, 900 University Avenue, Riverside, CA 92521, USA.
authors.forename: Seemanti
authors.initials: S
authors.lastname: Chakrabarti
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: King
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Cardona
authors.forename: Alec C
authors.initials: AC
authors.lastname: Gerry
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000830:Animals, Laboratory / Q000821:virology*; D002140:California; D041981:Gastrointestinal Tract / Q000821:virology; D006793:Houseflies / Q000821:virology*; D016015:Logistic Models; D009117:Muscidae / Q000821:virology*; D009522:Newcastle disease virus; D013997:Time Factors